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### Numerators and Denominators in Addition

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Date: 3/3/96 at 9:46:30
From: "David P. Lovett"

fractions with like denominators?
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Date: 3/4/96 at 21:55:45
From: Doctor Ken

Hello!

The answer to your question can actually be seen by looking at
the English language, of all things!  Let's say we have 3
oranges, and we add that to 5 oranges.  What do we get?  We get
8 oranges.  We DON'T get 8 (oranges+oranges).  That would be
pretty weird.

Well, the situation is just the same with fractions.  If we're
adding these things called "elevenths."  This fact is reflected
in how we say this sentence:"3 elevenths plus 5 elevenths equals
8 elevenths."If we replace "elevenths" with "oranges," we get
the same kind of thing: "3  oranges  plus 5  oranges  equals 8
oranges." So that's why.  Here's a question for you: why do we
need a common denominator in the first place?

-Doctor Ken,  The Math Forum

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Associated Topics:
Elementary Fractions

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